/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.api.common.typeutils.base;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.memory.DataInputView;
import org.apache.flink.core.memory.MemorySegment;

import java.io.IOException;
import java.time.LocalTime;

@Internal
public final class LocalTimeComparator extends BasicTypeComparator<LocalTime> {

	private static final long serialVersionUID = 1L;

	public LocalTimeComparator(boolean ascending) {
		super(ascending);
	}

	@Override
	public int compareSerialized(DataInputView firstSource, DataInputView secondSource) throws IOException {
		return compareSerializedLocalTime(firstSource, secondSource, ascendingComparison);
	}

	@Override
	public boolean supportsNormalizedKey() {
		return true;
	}

	@Override
	public int getNormalizeKeyLen() {
		return 7;
	}

	@Override
	public boolean isNormalizedKeyPrefixOnly(int keyBytes) {
		return keyBytes < getNormalizeKeyLen();
	}

	@Override
	public void putNormalizedKey(LocalTime record, MemorySegment target, int offset, int numBytes) {
		putNormalizedKeyLocalTime(record, target, offset, numBytes);
	}

	@Override
	public LocalTimeComparator duplicate() {
		return new LocalTimeComparator(ascendingComparison);
	}

	// --------------------------------------------------------------------------------------------
	//                           Static Helpers for Date Comparison
	// --------------------------------------------------------------------------------------------

	public static int compareSerializedLocalTime(DataInputView firstSource, DataInputView secondSource,
			boolean ascendingComparison) throws IOException {
		int cmp = firstSource.readByte() - secondSource.readByte();
		if (cmp == 0) {
			cmp = firstSource.readByte() - secondSource.readByte();
			if (cmp == 0) {
				cmp = firstSource.readByte() - secondSource.readByte();
				if (cmp == 0) {
					cmp = firstSource.readInt() - secondSource.readInt();
				}
			}
		}
		return ascendingComparison ? cmp : -cmp;
	}

	public static void putNormalizedKeyLocalTime(LocalTime record, MemorySegment target, int offset, int numBytes) {
		int hour = record.getHour();
		if (numBytes > 0) {
			target.put(offset, (byte) (hour & 0xff - Byte.MIN_VALUE));
			numBytes -= 1;
			offset += 1;
		}

		int minute = record.getMinute();
		if (numBytes > 0) {
			target.put(offset, (byte) (minute & 0xff - Byte.MIN_VALUE));
			numBytes -= 1;
			offset += 1;
		}

		int second = record.getSecond();
		if (numBytes > 0) {
			target.put(offset, (byte) (second & 0xff - Byte.MIN_VALUE));
			numBytes -= 1;
			offset += 1;
		}

		int nano = record.getNano();
		int unsignedNano = nano - Integer.MIN_VALUE;
		if (numBytes >= 4) {
			target.putIntBigEndian(offset, unsignedNano);
			numBytes -= 4;
			offset += 4;
		} else if (numBytes > 0) {
			for (int i = 0; numBytes > 0; numBytes--, i++) {
				target.put(offset + i, (byte) (unsignedNano >>> ((3 - i) << 3)));
			}
			return;
		}

		for (int i = 0; i < numBytes; i++) {
			target.put(offset + i, (byte) 0);
		}
	}
}
